Prognostic Value of Residual Coronary Artery Lesions on the SYNTAX Scale in Patients with Acute Myocardial Infarction without SТ Segment Elevation in the Mid-Term Period

Aim To study the effect of residual coronary injury after a percutaneous coronary intervention (PCI), as evaluated with the SYNTAX scale (residual SYNTAX score, RSS), on the mid-term prognosis for patients with non-ST elevation acute myocardial infarction (NSTEMI) and also to determine threshold RSS values for patients at high and low risk of adverse cardiac events.Material and methods A single-center, retrospective study was performed. From 421 patients with NSTEMI after PCI with stenting, 169 patients were selected who originally had multivessel coronary disease and who had undergone a repeated inpatient examination, including mid-term (11.7±3.0 mos.) coronary angiography. The endpoints were recurrent clinical manifestations of angina, repeat revascularization (RR), unstable angina (UA), recurrent acute myocardial infarction (AMI), cardiac death, and also a composite endpoint (major adverse cardiac events, MACE) that included UA, recurrent AMI, and cardiac death. After revealing a significant direct correlation between RSS and the probability of recurrent AMI, UA, MACE, or RR (p <0.05) using the ROC analysis, we have established threshold RSS values that divided patients into groups with high and low risk of the cardiac events listed above.Results For a significantly high risk of recurrent AMI (area under the curve, AUC 0.79±0.05; 95 % confidence interval, CI 0.68-0.89; р=0.048), the threshold RSS score was 8 (sensitivity 100 %, specificity 70.9 %). For UA and MACE, the RSS scores were both 3 (AUC 0.68±0.5; 95 % CI 0.58-0.79; p=0.005 and AUC 0.71±0.05; 95 % CI 0.61-0.8; p=0.001, respectively). The probability of UA during the observation period with RSS >3 was 4.07 times higher and that of MACE was 5.23 times higher than with RSS<3 (95 % CI 1.44-11.49; р=0.01 and 95 % CI 1.88-14.53; р=0.001, respectively).Conclusion The study demonstrated a significant, direct correlation between the RSS and the risk of adverse cardiac events in patients with NSTEMI during one year of observation. Specific threshold values were obtained, which may help in choosing both the extent of revascularization and the tactics for postoperative management of patients.